London: Marathon world record holder Paula Radcliffe described the International Olympic Committee's (IOC) refusal to ban Russia from the Olympics as a "sad day for clean sport" while cycling gold medalist Chris Hoy said officials had "passed the buck".

Individual sports federations will now have primary responsibility for determining every Russian athlete's eligibility for Rio, the IOC executive said, even though the Games get under way in less than two weeks' time.

"A sad day for clean sport," wrote 42-year-old Radcliffe, a four-time Olympian, on her Twitter account.

"A decision that shows that the IOC's primary concern is not to protect the clean athletes, not to be able to look them in the eye and promise they did all they could to ensure a level playing field.

"While it throws a political lifeline to Russia that surely came with promises and assurances, it is unfair to leave it up to federations at such short notice, particularly the smaller federations who will lack the resources to check the criteria."

Hoy, a six-time gold medallist in cycling, blasted the IOC for shirking their responsibilities to the Games and sport in general.

"What sort of message does this send out? Surely IOC's job is to make crucial decisions rather than passing the buck," Hoy tweeted.

What sort of message does this send out? Surely IOC's job is to make crucial decisions rather than passing the buck https://t.co/hJMEooFTRB

Radcliffe, a long-time vocal critic of doping in athletics, also criticised the discrepancy over some competitors with past convictions being allowed to take part in Rio while others remained sidelined.

"While I applaud no athlete going to the Games who has previously served a doping suspension -- this cannot fairly be only Russian athletes," she said.

"A truly strong message for clean sport would have been to ban all those who have been caught cheating. In short, it does not send the clear message it could have done that doping and cheating in all Olympic sport will never be tolerated."

Two-time gold medallist in rowing, James Cracknell, was equally scathing of the IOC, saying they had "bottled it".

"IOC passing the buck to individual federations on whether to allow Russian athletes to compete in Rio 2016. Bad day," he tweeted.

Britain's Olympic champion long jumper Greg Rutherford told the Guardian that he feared the IOC would not opt for the blanket ban.

"I had a terrible feeling that arms would be twisted," he said.

"We know the pros and the cons of a blanket ban, we know the risks of 'collective justice', but we also know the risk of not punishing a culture of doping that comes from the very top. I would say that the latter is a much greater threat to sport."